Geology Reference
In-Depth Information
Life cycle assessments provide a significant step forward in evaluating the impact
of any anthropogenic action on the environment. In this way, LCAs have become a
popular tool for evaluating consumed resources and environmental impacts of pro-
ducts and services. Furthermore, they are becoming increasingly mature, flexible,
comprehensive and transparent.
The most widely used LCA programs are Sima-Pro
4
and GaBi
5
. Both use the
EcoInvent database
6
, which contains a very broad and in most cases unique “inter-
national industrial life cycle inventory data on energy and material supply, resource
extraction, chemical and metal use, agricultural aspects, waste management and
transport services”. Even if this database deserves great merit, the reader will see
in Chap. 7 that EcoInvent makes for very crude estimations of energy consumption
and environmental impacts of metals production.
Those databases used in a LCA are far from being su
ciently reliable since the
compilation task is huge. In order to improve, they need to incorporate technological
changes as quickly as they appear. The great variability of countries and practices
also makes representative and reliable results for a number of studies di
cult to
obtain, for various reasons: a) the sample size of data might be short in many cases;
b) what is valid for one country is not so for another; c) many data are obtained
via non specific averages that cover either vast geographical areas or a lengthy time
series d) allocation rules of environmental impacts for co-products along production
chains are frequently a function of commodity market prices rather than physical
objective causes. The latter are in fact dictated by their cost formation processes.
Therefore whilst LCA software facilitates accounting procedures, their results
may not only be subjective but highly suspect, especially if the data input is itself
questionable (this is particularly the case for metals and minerals). More impor-
tantly, in the cradle-to-grave path there is evidence to suggest that these accoun-
tancy systems don't regularly supply data regarding resource depletion. To address
this topic, there have been various different methodologies proposed such as those of
Finnveden and Ostland (1997); Weidema (2000); Lindeijer et al. (2002); Steen and
Borg (2002); Steen (2006); Stewart and Weidema (2005); Yellishetty et al. (2009).
These methodologies can be in turn categorised into four main groups (Finnveden
and Ostland, 1997):
(1) aggregation of energy and materials on energy and mass basis;
(2) aggregation according to measure of reserve deposits and current consumption;
(3) aggregation of energy impacts based on future scenarios, e.g., impacts associated
with recovery to initial state;
(4) aggregation of exergy and/or entropy production.
4
See http://www.pre.nl
5
See http://www.gabi-software.com
6
See http://www.ecoinvent.ch/
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